It would have not made much diference to Ali's body of work in retrospect, but it might have taken some lustre off it in the short term.

What it would have done is made Norton a lineal heavyweight champion which would have boosted Kens standing, and which could have had some indirect concequences.

Norton is now a Joe Walcott type figure and anybody who beat him would also go up historicaly, especialy if it was for the title which he now held. If Ali had beaten any of them then that would increase the value of those wins.

Norton won second fight, the thing is they would not let Ali lose. Same in second Frazier fight, if Ali loses two in row, anyone realize how much money promoters, reporters, sports writers, publishers and many others, lose out on? Ali sold not cause of ability, but controversy and political following. Reporters would get asked to do extra articles for his fights, therefore more pay. So they overlooked bad decisions, even defended them.
Promoters made way more if Ali fought, so they made sure judges and refs would 'Do right thing"

Norton beat Ali big in fight 3, but they would not let him have title. Not then.